Fuzzy Modeling Approach for Designing Urban Land Grading System by Using Remote Sensing and Geographic Information Systems (the Case of Weldiya, Northen Ethiopia)
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Date
2014-05-05
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Addis Ababa University
Abstract
Land grade have a crucial role to play in that it classifies the urban land into different
level of valuation scales making it possible for urban land valuation. It would enable the
development of appropriate standard benchmark prices on the lease of land and for the
valuation of land related property. It also brings transparent and clear taxation systems
that could establish sound and efficient land marketing system that would facilitate
investment. However, the existing land grade system of the urban centers of Ethiopia like
Weldiya town has not been very successful in allowing the town to benefit from the
advantages of having an efficient land grading system. The major reasons behind the
limitations emanates from two main factors. The first reason is related to that paramount
factors have not been exhaustively considered in designing urban land grading system.
The second problem is related to a methodological approach how land grade is prepared
and implemented. Moreover, despite the fact that many geographical phenomena like
land grade have fuzzy characteristics, currently most of the geographic phenomena are
represented by crisp. Hence, the intent of this study is to develop conceptual fuzzy land
grade model that is helpful to bring flexible land grading and enables to give decision
makers an informed decision. In any of these methods, factor identification, weighting
and integrating GIS and fuzzy logic approaches are important prerequisites that serve as
platform to develop land grading. To design the conceptual model five main factors
(infrastructure, land use, topographic characteristics, visual and environmental factors
and population density) have been considered. Twenty four criteria were also considered
under each main factor.The study confirmed that among the identified factors
infrastructure takes the lion’s share that has 51% weighting influence and land use is in
second position with weight influence 25.6 %. Topography, environmental and visual
quality and population density factors have weight influence of 12.6%, 6.9% and 3.9 %
respectively. This study used FAHP to determine criteria weights. The fuzzy consistency
ratio (FCR) result was obtained 0.06. Based on the research findings, the most valuable
land is situated in the old section of the town (CBD) where comprehensive infrastructure
has been developed. The fuzzy analysis indicated that there is a gradual change in urban
land grading pattern. This indicated that flexibility is another characteristic of fuzzy logic
application. The final out put map indicated grade one, grade two, grade three have
positively increased by 5.37%, 4.28% and 2.85% respectively as compared to the existing
land grading. This situation is happened due to infrastructure development and expansion
of the town.
To sum up, this paper indicates the fuzzy modeling approach can avoid the loss of
information that often arises when the strict Boolean logic is used on the basis of the crisp
sets (Yes/No) and can produced a better and more reasonable result than crisp. It is also
concluded that FAHP is best alternative to determine the criteria weights from judgments
of decision-making domain of experts.
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Keywords
Fuzzy, Crisp, Land Grade, Master Plan, Urban Planning